Parallel cell electrochemical production of modified anolyte solution

ABSTRACT

A membrane-based electrochemical cell produces a first anolyte solution and a membrane-less electrochemical cell produces a bleach solution such as from a brine solution. The first anolyte solution and bleach solution are combined to form a modified anolyte solution. A dual electrochemical cell device includes two segments, one having a membrane-based electrochemical cell and the other having a membrane-less electrochemical cell, separated by a partition, and secured together into a single, unitary structure.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/662,912 filed Jun. 21, 2012, the disclosure of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention generally relates to production of anolytesolutions with electrochemical cells.

BACKGROUND

Electrochemical cells typically include an anode, a cathode, and amembrane therebetween. When the anode and cathode are powered, anolytesolution is produced in an anolyte space between the anode and themembrane. Catholyte solution may also be produced in a catholyte spacebetween the membrane and the cathode. In such typical electrochemicalcells a liquid, such as a brine solution, is coupled into the anolytespace to produce anolyte solution when the anode and cathode arepowered. Pure water is advantageously coupled into the catholyte space,although brine solution could also be coupled into that space instead.Alternatively, pure water may be coupled into the anolyte space andbrine solution coupled into the catholyte space.

The anolyte solution, and often the catholyte solution, produced by suchmembrane-based electrochemical cells have been considered to providecleaning capabilities such as for laundry, clean-in-place, and surfacecleaning purposes. But the anolyte solution produced thereby is usuallya low pH acid, which can be corrosive, may have free chlorine whichmight gas off, and may not be sufficiently stable in storage.

SUMMARY OF THE INVENTION

The present invention, in one aspect, provides a system and method forproducing a modified anolyte solution possessing desirable cleaningcapabilities, but without the drawbacks of the anolyte solutionsproduced by typical electrochemical cells. To that end, and inaccordance with one feature of the present invention, a membrane-lesselectrochemical cell is provided to produce a bleach solution from brinesolution with the bleach solution combined with anolyte solution from amembrane-based electrochemical cell to produce a modified anolytesolution. In particular, a membrane-less electrochemical cell ischaracterized in that it has an anode, a cathode, and a fluid space,such as a bleach space, therebetween uninterrupted by a membrane so asto produce bleach solution from brine solution in the bleach space whenthe anode and cathode thereof are powered.

The modified anolyte solution obtained by mixing the bleach solutionfrom the membrane-less cell with the anolyte solution from themembrane-based cell is still acidic and provides desirable cleaningcharacteristics. But, unlike the anolyte solution produced by themembrane-based cell, the modified anolyte solution has a higher pH andso is less corrosive, reduces the off-gassing, and is more stable forstorage.

The membrane-less cell and the membrane-based cell may be fluidicallycoupled as appropriate to sources of liquid, such as pure water and/orbrine solution, and to each other to mix the anolyte solution and bleachsolution to produce the modified anolyte solution. The anolyte space ofthe membrane-based cell and the fluid space of the membrane-less cellmay be coupled to a common source of liquid, such as brine solution, orthey may be coupled to different sources of liquid, such as pure waterand brine solution, respectively, or to different brine solutions (ordifferent concentrations of otherwise similar brine solutions). Themodified anolyte solution may be coupled to an anolyte tank for useand/or storage. Also, the catholyte solution produced by themembrane-based cell may be coupled to a catholyte tank for use and/orstorage, or may be disposed of as appropriate. In any event, because theanolyte solution from the first cell is mixed with the bleach solutionfrom the second cell, the two cells may be seen as being in parallel, atleast fluidically.

The present invention, in another aspect, provides a dualelectrochemical cell device to produce modified anolyte solution. Tothat end, and in accordance with this aspect of the present invention, aplurality of anode and cathode pairs are separated by a partition andsecured together as a single unit to define two segments ofelectrochemical cells in a unitary structure to either side of thepartition. In one segment, each anode and cathode pair has a membranebetween the anode and cathode thereof to define a membrane-basedelectrochemical cell, and in the other segment a fluid space between theanode and cathode of each anode and cathode pair is uninterrupted todefine a membrane-less electrochemical cell. The partition isadvantageously fluid impermeable such that in one unitary structure,there are two, effectively independent, electrochemical cells.

The membrane-based and membrane-less cells can be fluidically coupled ina number of ways, including in parallel fashion such that anolytesolution from the membrane-based cell is mixed with bleach solution fromthe membrane-less cell. Alternatively, the anolyte space of themembrane-based cell may be coupled to the fluid space of themembrane-less cell to couple the anolyte solution from themembrane-based cell into the fluid space of the membrane-less cellsegment such that when the anode and cathode of the membrane-less cellsegment are powered, anolyte solution therein is converted to modifiedanolyte solution. In that arrangement, the cell segments may be seen asbeing fluidically in series, rather than in parallel.

By virtue of the foregoing, there is thus provided, in one aspect, asystem and method for producing a modified anolyte solution possessingdesirable cleaning capabilities, but without the drawbacks of theanolyte solutions produced by typical electrochemical cells. There isfurther provided, in another aspect, a dual electrochemical cell device.These and other advantages of the present invention shall be madeapparent from the accompanying drawings and the description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the general description of the invention given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a diagrammatic depiction of a system of a fluidically parallelmembrane-based electrochemical cell and a membrane-less electrochemicalcell for producing modified anolyte solution in accordance with theprinciples of one aspect of the present invention;

FIG. 2 is a diagrammatic depiction of a system for producing modifiedanolyte solution including the system of fluidically parallelelectrochemical cells of FIG. 1;

FIG. 3 is an exploded, schematic view of an alternative embodiment of amembrane-based electrochemical cell for use in place of themembrane-based electrochemical cell of the systems of FIGS. 1 and 2;

FIG. 4 is an exploded, schematic view of an alternative embodiment of amembrane-less electrochemical cell for use in place of the membrane-lesselectrochemical cell of the systems the systems of FIGS. 1 and 2;

FIG. 5A is an exploded, schematic view of a dual electrochemical celldevice having a membrane-based electrochemical cell in one segment, amembrane-less electrochemical cell segment in another segment, and thesegments separated from one another by a partition in accordance withanother aspect of the present invention;

FIG. 5B is a diagrammatic depiction of the dual electrochemical celldevice of FIG. 5A with the cell components of each of the segments andthe partition secured together as a single unit or unitary structure;

FIG. 6 is a diagrammatic depiction of the dual electrochemical celldevice of FIGS. 5A and 5B, with the segments fluidically coupled inparallel; and

FIG. 7 is a diagrammatic depiction of the dual electrochemical celldevice of FIGS. 5A and 5B, with the segments fluidically coupled inseries.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to FIG. 1, there is shown a system 10 for producingmodified anolyte solution as at 12 in accordance with the principles ofthe present invention. System 10 includes a first electrochemical cell14 and a second electrochemical cell 16 fluidically coupled in parallelas will be described herein. The first electrochemical cell 14 may be aconventional membrane-based electrochemical cell and includes a pair offoraminous electrodes 20, 22, the electrode 20 being an anode and theelectrode 22 being a cathode. An ion exchange membrane 24 is situatedbetween the anode 20 and the cathode 22 such that the firstelectrochemical cell 14 may be seen as being a membrane-basedelectrochemical cell. An anolyte space 30 is provided between the anode20 and the membrane 24, and a catholyte space 32 is provided between thecathode 22 and the membrane 24.

A first liquid 34 may be introduced into the anolyte space 30 via afirst input 35 coupled to the anolyte space 30. The first input 35 maybe connected directly into the anolyte space 30 and/or indirectlythrough the anode 20, such as through apertures 20′ therein (FIG. 3). Asecond liquid 36 may be introduced into the catholyte space 32 via asecond input 37 coupled to the catholyte space 32. The second input 37may be connected directly into the catholyte space 32 and/or indirectlythrough the cathode 22, such as through apertures 22′ therein (FIG. 3).When the electrodes 20, 22 are powered such as by a power supply 38(FIG. 2), a first anolyte solution 40 is produced in the anolyte space30 from the first liquid 34 and is accessible at a first output 41coupled to the anolyte space 30. Also, a catholyte solution 42 isproduced in the catholyte space 32 from the second liquid 36 and isaccessible at a second output 43 coupled to the catholyte space 32. Thefirst output 41 may be connected directly into the anolyte space 30and/or indirectly through the anode 20, such as through apertures 20′therein. Similarly, the second output 43 may be connected directly intothe catholyte space 32 and/or indirectly through the cathode 22, such asthrough apertures 22′ therein. As can be seen, inputs 35 and 37 are toone side of electrochemical cell 14 with outputs 41 and 43 beingdisposed to an opposite side thereof.

Where the membrane 24 is a cation exchange membrane, the first liquid 34is advantageously a brine solution. The second liquid 36 may be either abrine solution or pure water. Where the membrane is an anion exchangemembrane, the second liquid 36 is advantageously a brine solution, andthe first liquid 34 may be either a brine solution or pure water.

The second electrochemical cell 16 may be a conventionalnon-membrane-based electrochemical cell and includes a pair of solid,i.e., non-foraminous, electrodes 50, 52, the solid electrode 50 being ananode and the solid electrode 52 being a cathode. A fluid space 54, suchas a bleach space, between the solid electrodes 50, 52 is uninterruptedby a membrane, such that the second electrochemical cell 16 may be seenas being a membrane-less electrochemical cell. A third liquid 60, whichis advantageously a brine solution, may be introduced into the bleachspace 54 via a third input 61 coupled to the bleach space 54. Whenelectrodes 50, 52 are powered such as by a power supply 38 (FIG. 2), ableach solution 62, such as a sodium hypochlorite bleach, is produced inthe bleach space 54 from the third liquid 60 and is accessible at athird output 63 coupled to the bleach space 54. The third input 61 maybe connected directly into the bleach space 54. Similarly, the thirdoutput 63 may be connected directly into the bleach space 54. It will beappreciated that while anode 50 and cathode 52 are advantageously solid,if either or both of them were foraminous instead, then the third input61 or the third output 63 may be connected indirectly into the bleachspace 54 through the anode 50 or cathode 52 via apertures (not shown)therein. As can be seen, input 61 is to one side of electrochemical cell16 with output 63 being disposed to an opposite side thereof.

In accordance with one aspect of the present invention, the cells 14 and16 are fluidically in parallel. To that end, the anolyte space 30 andbleach space 54 are in fluid communication so as to mix the firstanolyte solution 40 and the bleach solution 62 to produce the modifiedanolyte solution 12. The first and third outputs 41, 63 are coupledtogether so that the first anolyte solution 40 and the bleach solution62 mix to produce the modified anolyte solution 12. The first and thirdoutputs 41, 63 are also coupled to a further output 64 from which themodified anolyte solution 12 is accessible.

Inputs 35 and 37 may be coupled together such that the first and secondliquids 34 and 36 introduced into the anolyte space 30 and the catholytespace 32 may be the same and from a common source. Or the inputs 35 and37 may be independent such that first and second liquids 34 and 36introduced into the anolyte space 30 and the catholyte space 32 may befrom different sources and so can be different liquids. Similarly,inputs 35 and 61 may be coupled together such that the first and thirdliquids 34 and 60 introduced into the anolyte space 30 and the bleachspace 54 may be the same and from a common source, particularly whereboth liquids are to be a brine solution. Alternatively, inputs 37 and 61may be coupled together such that the second and third liquids 36 and 60introduced into the catholyte space 32 and the bleach space 54 may bethe same and from a common source, particularly where both liquids areto be a brine solution. Further alternatively, all three of inputs 35,37, and 61, may be coupled together such that the first, second, andthird liquids 34, 36, and 60 introduced into the anolyte space 30, thecatholyte space 32, and the bleach space 54 may be the same and from acommon source, particularly where all three liquids are to be a brinesolution. Or all three of the inputs 35, 37, and 61, may be independentsuch that the first, second, and third liquids 34, 36, and 60 introducedinto the anolyte space 30, the catholyte space 32, and the bleach space54 may be from different sources and so can be different liquids. As aconsequence, the brine solution used in cell 14 may be different, or ofa different concentration, than the brine solution use in cell 16, byway of example.

A typical brine solution used for the third liquid 60 and/or for eitheror both of the first and second liquids 34 and 36, is a saline solutionwherein the electrolyte is NaCl at a concentration of 0.5 to 2.5 g/l.However, other brine solutions of other salts and/or concentrations maybe used. By way of example, the electrolyte could be KCl. In regard tothe third liquid 60, irrespective of the electrolyte involved, thesolution 62 produced by the cell 14 is considered a bleach solution.

Referring next to FIG. 2, a system 70 for producing modified anolytesolution 12 includes the fluidically parallel first and secondelectrochemical cells 14, 16 of system 10 with membrane 24 being acation exchange membrane, as well as a liquid input assembly 72 forproducing the first, second, and third liquids 34, 36, 60, and a productoutput assembly 74 for handling the first anolyte solution 40, thecatholyte solution 42, the bleach solution 62, and the modified anolytesolution 12.

The liquid input assembly 72 includes a tap water conduit 78 connectablewith a supply of water 80, such as a municipal water source. A tap watercontrol valve 82 is coupled with the tap water conduit 78 and regulatesthe flow of tap water through the tap water conduit 78. The tap watercontrol valve 82 can be actuated manually or electronically. The tapwater conduit 78 is also coupled with a water filter 84, which may beany appropriate water filter the selection of which may depend on thequalities of the supply of water used. For example, the water filter 84may include diatomaceous earth or carbon media, filter elements ofvarious porosity sizes, such as 25-microns, 10-microns, and 5-microns,combinations of the same, or other appropriate filtering devices. Afiltered water conduit 86 receives water that has been processed by thewater filter 84 and is coupled with a water softener 88. The selectionof the water softener 88 may also depend on the qualities of the supplyof water used. For example, the water softener 88 can be a standard ionexchange water softener or a reverse osmosis unit. A water purificationdevice (not shown) can also advantageously be included in the liquidinput assembly 72.

Water that has passed through the water filter 84 and the water softener88 is referred to herein as pure water and coupled through a pure waterconduit 90 to be available as the second liquid 36 for the firstelectrochemical cell 14 via a second conduit 92 coupled to the input 37and via a third conduit 94 to a brine tank 100 as will be described.Advantageously, the pure water could also be diverted and stored in atank (not shown) for later use.

The liquid input assembly 72 further includes the brine tank 100 and abrine pump 102. Pure water is coupled with the brine tank 100 via theconduits 90, 94 to create a brine solution precursor. The brine solutionprecursor formed in the brine tank 100 is pumped at controlled levels bythe brine pump 102 through a brine solution precursor conduit 104 andinto a fourth conduit 105 which couples pure water from conduit 90 as tomix with the brine solution precursor to form a brine solution to beavailable as the first liquid 34 for the first electrochemical cell 14via a fifth conduit 106 coupled to the inlet 35, and as the third liquid60 via a sixth conduit 107 coupled to the fifth conduit 106 and theinlet 61. The brine pump 102 is advantageously controlled so that thebrine solution achieves a target electrical conductivity.

To that end, a controller 108 receives a signal from a conductivitysensor 109 which measures the electrical conductivity of the brinesolution in the fifth conduit 106. That signal is used by controller 108to control the rate or speed of brine pump 102 whereby to adjust theamount of brine precursor solution to mix with the pure water. In oneembodiment, the controller 108 generates a control signal to the pump102 in the range of 4-20 mA.

Input conduit control valves 110 a, 110 b, 110 c are provided in theconduits 92, 106, and 107, respectively for controlling the flow of therespective liquids into the respective spaces of the electrochemicalcells 14, 16. The input conduit control valves 110 a, 110 b, 110 c canbe actuated manually or electronically.

Controller 108 also causes the power supply 38 to power the anodes andcathodes 20, 22 and 50, 52 of the cells 14, 16 to produce the firstanolyte solution 40, the catholyte solution 42, the bleach solution 62.

The product output assembly 74 includes a catholyte conduit 112 and acatholyte tank 114. The catholyte conduit 112 is coupled with the secondoutput 43 and the catholyte tank 114 to fluidically couple the catholytespace 32 and the tank 114 which receives the catholyte solution 42.

The product output assembly 74 also includes an anolyte conduit 116 anda bleach conduit 118 coupled with the first output 41 and the thirdoutput 63, respectively, and the further output 64 so as to mix thefirst anolyte solution 40 and the bleach solution 62 to form themodified anolyte solution 12 to be accessible at the further output 64.The product output assembly 74 also includes a modified anolyte conduit120 and an anolyte tank 122. The modified anolyte conduit 120 is coupledwith the further output 64 and the anolyte tank 122 to fluidicallycouple the modified anolyte solution 12 to be received in the anolytetank 122.

The pH of the modified anolyte solution 12 is monitored with a pH sensor124 coupled to the modified anolyte conduit 120. Signals from the pHsensor 124 are coupled to the controller 108 which generates controlsignals to the power supply 38 to cause the power supply 38 to power theanode 50 and cathode 52 at a constant current, which may be adjusted orset as desired. The first anolyte solution 40 may be at a pH of about1-3. The desired pH of the modified anolyte solution 12 is about 4-5.Hence, the controller 108 causes the constant current output from thepower supply 38 to adjust to a level sufficient to result in a pH forthe bleach solution 60 which will cause the modified anolyte solution 12to have a pH of approximately 4-5. While only one power supply 38 isshown for both electrochemical cells 14, 16, separate power supplies maybe used. For example, power supply 38 may be used to power electrodes50, 52 of the second electrochemical cell 16 and a separate power supply(not shown) may be used to power the electrodes 20, 22 of the firstelectrochemical cell 14. That separate power supply may also get controlsignals from controller 108, but the signals may be preset or useradjustable, rather than in response to any characteristic of the liquidsinvolved in the system 70.

Further, while the catholyte solution 40 is shown as being received in acatholyte tank 114, it could alternatively be disposed of directlyrather than via such a tank. In any event, the modified anolyte solution12 and the catholyte solution 40 are available for immediate use fromthe tanks 122, 114 respectively, or for later use with the tanks 122,114 serving as storage vessels for the respective solutions.

In use, the liquids 34, 36, and 60 are coupled with the firstelectrochemical cell 14 and the second electrochemical cell 16, and therespective anodes 20, 50 and cathodes 22, 52 of the electrochemicalcells 14, 16 are powered to create the first anolyte solution 40, thecatholyte solution 42, and the bleach solution 62. In particular, abrine solution is introduced into the anolyte space 30 in the firstelectrochemical cell 14 and the bleach space 54 in the secondelectrochemical cell 16. Additionally, pure water is introduced into thecatholyte space 32 in the first electrochemical cell 14. When the anode20 and cathode 22 in the first electrochemical cell 14 are powered,first anolyte solution 40 and catholyte solution 42 are produced in theanolyte and catholyte spaces 30, 32, respectively. Similarly, when theanode 50 and cathode 52 in the second electrochemical cell 16 arepowered, bleach solution 62 is produced in the bleach space 54. Thefirst anolyte solution 40 and bleach solution 62 are mixed to form themodified anolyte solution 12. The modified anolyte solution 12 can becoupled with, or directed to, the anolyte tank 122, and the catholytesolution 42 can be coupled with, or directed to, the catholyte tank 114.The modified anolyte solution, and the catholyte solution if desired,may be used for cleaning purposes such as for laundry, surface cleaning,or within piping such as for clean-in-place applications.

In particular, the first anolyte solution 40 produced in the firstelectrochemical cell 14 will have a pH in the range of about 1-3, andthe catholyte solution 42 produced in the first electrochemical cell 14will have a pH in the range of about 11.5-12. The bleach solution 62produced in the second electrochemical cell 16 will have a pH in therange of about 8.5-9.5, and the modified anolyte solution 12 will have apH of about 4-5. Thus, mixing the first anolyte solution 40 with thebleach solution 62 provides a modified anolyte solution 12 having ahigher pH than the first anolyte solution 40 alone. Without beinglimited to any particular theory or mechanism, it is believed that a pHof about 4-5 increases the solubility of active chlorine in the modifiedanolyte solution 12 and decreases the corrosion potential associatedwith lower pH values. Thereby, the modified anolyte solution 12 has aless extreme pH value than the first anolyte solution 40 and while itprovides the desired cleaning properties, it overcomes the drawbacksthat would have been expected from the first anolyte solution 40.

In the systems 10 and 70 described herein, the first electrochemicalcell 14 includes only one pair of electrodes 20, 22 and one membrane 24.Alternatively, multiple pairs of electrodes 20, 22 each with arespective membrane 24 therebetween could be employed. To that end, andwith reference to FIG. 3, an alternative embodiment of a conventionalmembrane-based first electrochemical cell 14′ is shown in an exploded,schematic view with like parts between cells 14 and 14′ bearing the samereference numbers.

FIG. 3 shows that the first electrochemical cell 14′ includes aplurality of anolyte spaces 30 and catholyte spaces 32. As shown, theplurality of anodes 20 and cathodes 22 are arranged so as to provideadjacent anolyte spaces 30 and catholyte spaces 32. Adjacent respectiveanolyte spaces 30 and catholyte spaces 32 are separated by a spacer 130.The anodes 20 and cathodes 22 in adjacent anolyte and catholyte spaces30, 32 are arranged in an opposite manner so that the same types ofelectrodes (either anodes or cathodes) border the spacers 130 betweenthe spaces 30, 32. For example, a set of components in the firstelectrochemical cell 14′ may be arranged in the following order:anode-membrane-cathode-spacer-cathode-membrane-anode-spacer. Thispattern is repeated for the number of anolyte and catholyte spaces 30,32 in the cell.

All the anodes 20 in the first electrochemical cell 14′ are electricallycoupled to one another and to the power supply 38. Similarly, all thecathodes 22 in the first electrochemical cell 14′ are electricallycoupled to one another and to the power supply 38.

A gasket 132 separates adjacent components in the first electrochemicalcell 14′. Thus, a gasket 132 is positioned between each anode 20 andmembrane 24, between each cathode 22 and membrane 24, and between eachcathode 22 or anode 20 and each spacer 130. In addition, spacers 130 andassociated end plates 133 are included at each end to close off the lastof the plurality of anodes 20 and anolyte spaces 30, and the last of theplurality of cathodes 22 and catholyte spaces 32.

The anodes 20, cathodes 22, and membranes 24 in the firstelectrochemical cell 14′ are generally planar, and can have any suitablecomposition. The gaskets 132, spacers 130, and end plates 133 are alsoplanar such that when compressed together from end to end, they can besecured such as by bolts (not shown) drawing the end plates 133 togetherwith the components therebetween brought together into a fluid tight(except for the inlets and outlets) assembly. Advantageously, the anodes20 are foraminous (thus having apertures 20′therethrough) and are madeof pure titanium coated with RuO₂ and IrO₂, and the cathodes 22 areforaminous (thus having apertures 22′ therethrough) and are made ofuncoated pure titanium, although in other embodiments, they could besolid. Also advantageously, the RuO₂ and IrO₂ of the anode coating arepreferably present in equal amounts, but the ratio may also vary fromabout 60/40 to about 40/60. The membranes 24 in the firstelectrochemical cell 14′ are advantageously cation exchange membranes,but could be anion exchange membranes.

As shown, each input 35 is associated with a respective spacer 130adjacent an anolyte space 30 (or between adjacent anolyte spaces 30) soas to fluidically couple the first liquid 34 into the respective anolytespaces 30 through the apertures 20′ in the anodes 20. The inputs 35 arealso fluidically coupled to the conduit 106 so the same liquid (brinesolution) can be coupled to each anolyte space 30. Likewise, each input37 is associated with a respective spacer 130 adjacent a catholyte space32 (or between adjacent catholyte spaces 32) so as to fluidically couplethe second liquid 36 into the respective catholyte spaces 32 through theapertures 22′ in the cathodes 22.

The inputs 37 are also fluidically coupled to the conduit 92 so that thesame liquid (pure water) can be coupled to each catholyte space 32. In asimilar manner, each output 41 is associated with a respective spacer130 adjacent an anolyte space 30 (or between adjacent anolyte spaces 30)so as to fluidically couple the first anolyte solution 40 out of therespective anolyte spaces 30 through the apertures 20′ in the anodes 20.The outputs 41 of the anolyte spaces 30 are fluidically coupled to theanolyte conduit 116 to combine the first anolyte solution 40 from all ofthe spaces 30 to be mixed with the bleach solution 62. Similarly, eachoutput 43 is associated with a respective spacer 130 adjacent acatholyte space 32 (or between adjacent catholyte spaces 32) so as tofluidically couple the catholyte solution 42 out of the respectivecatholyte spaces 32 through the apertures 22′ in the cathodes 22. Theoutputs 43 of the catholyte spaces 32 are fluidically coupled to thecatholyte conduit 112 to combine the catholyte solution 42 for receiptby the catholyte tank 114.

Given the generally planar construction of the anodes 20, cathodes 22,and membranes 24, the anolyte and catholyte spaces 30, 32 have a majorlengthwise dimension, and the inputs 35, 37 and outputs 41, 43 arearranged on opposite sides of that lengthwise dimension. Thus, eachanolyte space 30 and each catholyte space 32 extends lengthwise betweenan area generally adjacent a respective input 35, 37 to an areagenerally adjacent a respective output 41, 43.

Referring next to FIG. 4, an alternative embodiment of a conventionalnon-membrane-based second electrochemical cell 16′ is shown in anexploded, schematic view with like parts between cells 16 and 16′bearing the same reference numbers. In second electrochemical cell 16′ aspacer 134 is included between the anode 50 and the cathode 52, andgaskets 136 are positioned between the anode 50 and the spacer 134, thecathode 52 and the spacer 134, and between the anode 50 and cathode 52and respective end plates 137. The third inlet 61 and third output 63are associated with opposite ends of the spacer 134 to couple the thirdliquid 60 into, and the bleach solution 62 out of, the bleach space 54defined within spacer 134 between anode 50 and cathode 52. Further, theanode 50 and cathode 52 of the second electrochemical cell 16′ mayadvantageously be solid metal plates of pure titanium (the anode mayalso be coated with RuO₂ and IrO₂ like the anodes 20 of the firstelectrochemical cells 14, 14′). Like cell 14′, the components of cell16′ are advantageously planar and may be compressed and secured togetherinto a fluid tight (except for the inlet 61 and outlet 63) assembly.

In use, the first and second electrochemical cells 14′, 16′ eachfunction in a similar manner as the first and second electrochemicalcells 14, 16 described above.

In accordance with a second aspect of the present invention, and asshown in FIGS. 5A, 5B, 6, and 7, a dual electrochemical cell device 200is provided for producing modified anolyte solution by, in effect,compressing the respective anodes, cathodes, spacers, gaskets, and endplates of the cells 14′ and 16′ together end to end into a fluid tight(except for the inlets and outlets) assembly. To that end, a pluralityof anode and cathode pairs 202 are separated by a partition 204 (insteadof end walls 133 and 137, which are at respective ends of the device 200as seen particularly in FIG. 5B) and secured together as a singleunitary structure 206. The partition 204 divides the dual cell device200 into two segments of electrochemical cells, with one electrochemicalcell on each side of the partition 204. In particular, a firstelectrochemical cell 210 is included in a first segment 212, and asecond electrochemical cell 214 is included in a second segment 216. Thepartition is advantageously fluid impermeable such that in the oneunitary structure 206, there are two, effectively independent,electrochemical cells 210, 214. The first cell 210 is a membrane-basedelectrochemical cell and produces a first anolyte solution 218. Thefirst cell 210 may also produce a catholyte solution 220. The first cell210 is of similar construction and operates in a similar manner as thefirst electrochemical cells 14 and 14′ described above. The second cell214 is a membrane-less electrochemical cell, and according to one aspectof the present invention, produces a liquid solution 222. The secondcell 214 is of similar construction to that of the secondelectrochemical cells 16 and 16′ described above.

In particular, one or more anode and cathode pairs 202 in the first cell210 each include a membrane 230 between the respective anode 232 andcathode 234 thereof. An anolyte space 236 is provided between each anode232 and each membrane 230, and a catholyte space 238 is provided betweeneach cathode 234 and each membrane 230. The first cell 210 includesinputs and outputs like those described above for cell 14′. The anode232 and cathode 234 are advantageously foraminous, and the membrane 230is an ion exchange membrane which is advantageously a cation exchangemembrane.

In the second cell 214, a fluid space 244 between an anode 240 and acathode 242 of that pair 202 is uninterrupted by a membrane. The anode240 and cathode 242 are advantageously solid. The second cell 214includes inputs and outputs like those described above for cell 16′.FIG. 5A shows the various components of device 200 in an exploded view,with the components being compressed together into a unitary, fluidtight (except for the inlets and outlets) assembly being shownschematically in FIG. 5B. In that regard, bolts 205, which may beinsulated to pass through exposed aspects of the anode and cathode pairs202, pull ends 133, 137 tightly together with the intervening, generallyplanar components sandwich therebetween into a generally fluid tight(except for the inlets and outlets thereof) assembly 200.

The first and second cells 210, 214 can be fluidically coupled in anumber of ways. As shown in FIG. 6, the first and second cells 210, 214are fluidically coupled in parallel. To that end, brine solution coupledto the anolyte spaces 236 of the first cell 210 produces therefrom firstanolyte solution 218, and brine solution coupled to the fluid space 244of the second cell 214 produces therefrom a bleach solution 222. Thefirst anolyte solution 218 from the first cell 210 is mixed with thebleach solution 222 from the second cell 214 to form a modified anolytesolution 250.

Alternatively, and as shown in FIG. 7, the first and second cells 210,214 can be fluidically coupled in series. To that end, brine solutioncoupled to the anolyte spaces 236 of the first cell 210 producestherefrom first anolyte solution 218 which is introduced into the fluidspace 244 of the second cell 214 to produce therefrom a modified anolytesolution 252 when the anode 240 and cathode 242 are powered.

By virtue of the foregoing, there is provided a system and method forproducing a modified anolyte solution possessing desirable cleaningcapabilities, but without the drawbacks of the anolyte solutionsproduced by typical electrochemical cells. There is further provided, inanother aspect, a dual electrochemical cell device.

While the present invention has been illustrated by a description ofparticular embodiments thereof and specific examples, and while theembodiments have been described in some detail, they are not intended torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. For example, the membrane-based cells 14, 14′and 210 include a single membrane between the anode(s) and thecathode(s) thereof, the principles described herein are equallyapplicable to other configurations. By way of example, a second membranecould be included between the first membrane and the cathode, with thecatholyte space being defined between the second membrane and thecathode. It will be seen, however, that the catholyte space is stillnecessarily between the first membrane and the cathode as well.Additionally, the space between the two membranes could contain a brinesolution with other liquids in the anolyte and catholyte spaces, such aspure water and/or other brine solutions. The invention in its broaderaspects is therefore not limited to the specific details, representativeapparatus and methods and illustrative examples shown and described.Accordingly, departures may be made from such details without departingfrom the scope or spirit of the general inventive concept.

Having described the invention, what is claimed is:
 1. A system forproducing modified anolyte solution comprising: a first electrochemicalcell having a first anode, a first cathode, and an ionic exchangemembrane therebetween, and having an anolyte space between the membraneand the first anode and a catholyte space between the membrane and thefirst cathode, whereby a first anolyte solution is produced from liquidin the anolyte space with the first anode and first cathode beingpowered; and a second electrochemical cell having a second anode and asecond cathode and having a bleach space between the second anode andthe second cathode uninterrupted by a membrane, whereby a bleachsolution is produced from a brine solution in the bleach space with thesecond anode and second cathode being powered; the anolyte space and thebleach space being in fluid communication so as to mix the first anolytesolution and the bleach solution, whereby to produce a modified anolytesolution as a mixture of the first anolyte solution and the bleachsolution.
 2. The system of claim 1 further comprising respective outputscoupled to the anolyte space and the bleach space, the respectiveoutputs being coupled so as to provide at a further output the modifiedanolyte solution.
 3. The system of claim 1 further comprising an anolytetank for receiving the modified anolyte solution.
 4. The system of claim1, whereby a catholyte solution is produced from liquid in the catholytespace with the first anode and first cathode being powered, the systemfurther comprising a catholyte tank for receiving the catholytesolution.
 5. The system of claim 4 further comprising an output coupledto the catholyte space, the output being fluidically coupled to thecatholyte tank.
 6. The system of claim 1, the membrane being a cationexchange membrane.
 7. The system of claim 1, the membrane being an anionexchange membrane.
 8. The system of claim 1, the first anode and thefirst cathode being foraminous, and the second anode and the secondcathode being solid.
 9. The system of claim 1, the first electrochemicalcell comprising a plurality of first anodes, a plurality of firstcathodes, and a plurality of respective ion exchange membranestherebetween to define a plurality of anolyte spaces between therespective membranes and first anodes and a plurality of catholytespaces between the respective membranes and first cathodes, whereby afirst anolyte solution is produced from liquid in the anolyte spaceswith the first anodes and first cathodes being powered.
 10. The systemof claim 9, the plurality of anolyte spaces and plurality of catholytespaces being arranged to provide adjacent anolyte spaces and adjacentcatholyte spaces.
 11. The system of claim 10 further comprising spacersbetween the anolyte spaces of adjacent anolyte spaces and between thecatholyte spaces of adjacent catholyte spaces.
 12. The system of claim1, the first cathode and first anode being generally planar.
 13. Thesystem of claim 1, the membrane being generally planar.
 14. The systemof claim 1, the second cathode and second anode being generally planar.15. A method of producing modified anolyte solution comprising:producing a first anolyte solution in an anolyte space between a firstanode and an ionic exchange membrane of a first electrochemical cellhaving the first anode, a first cathode, and the membrane therebetween;producing a bleach solution in a bleach space between a second anode anda second cathode of a second electrochemical cell having the secondanode and the second cathode uninterrupted by a membrane therebetween;and combining the first anolyte solution and the bleach solution to forma modified anolyte solution.
 16. The method of claim 15, producing thefirst anolyte solution including coupling brine solution to the anolytespace and powering the first anode and cathode.
 17. The method of claim16 further comprising coupling liquid to a catholyte space between themembrane and the cathode of the first electrochemical cell.
 18. Themethod of claim 17 further comprising producing a catholyte solution inthe catholyte space.
 19. The method of claim 15, producing the bleachsolution including coupling brine solution to the bleach space andpowering the second anode and cathode.
 20. The method of claim 15wherein the first anode and the first cathode are foraminous and thesecond anode and the second cathode are solid.
 21. A dualelectrochemical cell device comprising: a plurality of anode and cathodepairs a partition between two of the pairs to define first and secondsegments, a first of the anode and cathode pairs being in the firstsegment, a second of the anode and cathode pairs being in the secondsegment; and an ion exchange membrane disposed between the anode andcathode of the first pair, a fluid space between the anode and cathodeof the second pair being uninterrupted by a membrane, the anode andcathode pairs and the partition being secured together as a single,unitary, generally fluid tight assembly.
 22. The device of claim 21, thepartition being fluid impermeable.
 23. The device of claim 21, the anodeand cathode of the first pair being foraminous, and the anode andcathode of the second pair being solid.
 24. The device of claim 21, themembrane being a cation exchange membrane.
 25. The device of claim 21,the membrane being an anion exchange membrane.
 26. The device of claim21 further comprising a first input and a first output coupled to acatholyte space between the membrane and cathode of the first pair, asecond input and a second output coupled to an anolyte space between themembrane and the anodes of the first pair, and a third input and a thirdoutput coupled to the fluid space between the anode and the cathode ofthe second pair.
 27. The device of claim 26, second and third outputsbeing fluidically coupled whereby to combine fluids from the anolyte andfluid spaces.
 28. The device of claim 26, the second output beingcoupled to the third input.
 29. The device of claim 26, the anodes andcathodes being generally planar.